Out of the Fire (and into a bigger one)
by impertinentfool
Summary: Meeting so-called heroes and having several people after his head weren't entirely new experiences for him, but then again, he's never crash-landed into a different world before. This wasn't part of his plan. /Or, the Titan Lord Kronos is stuck in his vessel's body and accidentally flings himself into the Boku no Hero Academia universe. Lord have mercy.


**out of the fire (and into a bigger one)**

 **Summary:** Meeting so-called heroes and having several people after his head weren't entirely new experiences for him, but then again, he's never crash-landed into a different world before. This wasn't part of his plan. /The Titan Lord Kronos is stuck in his vessel's body and accidentally flings himself into the Boku no Hero Academia universe. Lord have mercy.

 **Warning(s): Slight profanity (aka Bakugou's mouth)**

 **Set in the timeline of The Last Olympian (near the ending) and before the events of Season Two of Boku no Hero Academia.**

* * *

 **Chapter One**

 **The Titan Lord of Time Makes a Breaking Entrance**

* * *

He was dying.

 _He was dying._

Pain was flaring up in every part of his body. It was as though he was slowly burning in a furnace, his body desperately trying to withstand the sensation of exploding inside-out from the building pressure and heat. It hurt. It hurt so much. He was used to being invincible. Right now, finally being mortal…

 _You traitorous fool,_ Kronos (the bastard was still inside him) seethed. _We were so close to victory. So close to crushing the gods. We could've ruled the world._

 _Not_ we. You, Luke thought. _And you hurt Annabeth. You hurt my family. I don't care if you're a Titan. Hurting Annabeth is the last straw._

 _Damn you, Luke Castellan,_ Kronos hissed in his mind. _You shouldn't have been my host. It should have been Perseus instead. You've ruined everything!_

 _You're still talking? You're such a persistent bastard. I really am an idiot for siding with you. But I'll fix my mistakes. I'll fix everything. It's time for you to go back to Tartarus. Permanently. That hell is where you belong._

The Titan howled, and Luke smiled, closing his eyes.

 _NO! I will not be defeated this easily._

Suddenly-

The air around him shifted, and something in him felt strange. His surroundings were changing, morphing, into some kind of abstract background. White noise invaded his ears. What was happening?

 _What are you doing?_

 _I am the King of Titans, you fool. I can bend time and space to my will,_ Kronos cackled. _I will NOT let my essence be scattered again just because of an idiot._

Luke's heart stopped in his chest. His entire left side was covered in thick blood- _his blood_ -and the world was starting to spin around him. He didn't know what to do. He felt so weak, so tired. He just wanted to close his eyes and rest for all eternity.

 _It was a mistake to underestimate me._

The throne room of the Olympians shook from the pure force of the Titan's magic.

The last thing he saw was Percy and Annabeth, battered and bruised and bloodied, looking at him in horror before everything turned black. And then-

he

was

falling-

 _I'm sorry, Annabeth._

* * *

Class 1-A was completely silent, except for the sound of papers being turned and pencils being used.

Midoriya Izuku set his pencil down and let out a huge sigh of relief. _I've finally finished answering all the questions_. He scanned his exam paper once, twice, just to double-check his answers and to make sure that he left no question unanswered. And then re-checked again. Just for good measure.

After doing that, he looked around the room. To his back, Yaoyorozu and Todoroki were also finished (as expected) and were just staring at the board, patiently waiting for the exam to end. Kirishima was still furiously scribbling on his paper as though it was the hardest exam he's ever done in his entire life. Ashido and Kaminari were gazing at their papers with a blank stare, with an expression that seemed as though they knew the end of the world was near. Sero still wasn't finished answering, and Aoyama seemed to just give up on finishing and was dozing off in the corner along with Ojiro. Shouji and Mineta seemed to finish already. In front of him, Bakugou was playing idly with his pencil, obviously done with the exam.

Izuku tore his gaze away from the rest of his classmates and turned to see his two closest friends inside the class. Iida kept on scrutinizing his exam paper with a concentrated look on his face, and Uraraka was resting her head on the palm of her hand, staring down at her paper, eyebrows furrowed and determined expression on her face.

When she felt his eyes on her, she turned her head towards him and stared back, and then gave him a somewhat discreet thumbs-up and an encouraging smile.

He felt his face go hot. He felt embarrassed for being caught staring, but at the same time he felt warm and happy inside for no reason. He didn't want to rationalize that it was probably because Uraraka smiled at him.

It was the last day of their mid-term exams. Today was the last hurdle before they would advance to more advanced hero combat training, and everyone was thrumming with nervous energy amidst the pressure of the three-day written examination-

Suddenly, the hairs on the back of his neck stood up and goosebumps spread around his arms. He felt an oppressive, achingly odd presence, near and approaching, coming from somewhere, somewhere _above_ -

He heard it before he saw what it was.

 _Boom!_

 _Boom!_

 _BOOM!_

Dust and rubble came flying everywhere. The entire classroom floor cracked, and the impact was so great it sent nearby desks and chairs careening, which-unfortunately-included him. Izuku stumbled down, mind in a daze, and slowly stood up as he tried to pinpoint the cause of all the sudden chaos and destruction.

"What-what the _hell_ was that-"

"Oh god, are aliens invading us?"

"Was that a bomb?!"

"Let's get out of here! It might be something dangerous!"

"Everyone, calm down!"

"Oi, Iida, this is serious! What the hell was that?! Where did it come from?!"

"It came from above! Up there!" Sato yelled, voice almost hysterical.

There were sounds of coughing everywhere due to the ash, and the entire class instantly prepared their quirks, ready for battle. If it proved that _whatever_ it was was dangerous, then it would regret ever coming to Class 1-A.

"What if it's another villain attack?" Kaminari asked.

"Man, not again!" Kirishima.

"I hope not." That voice was from Tsuyu.

When the smoke cleared, Izuku realized with a sinking heart that the source crash-landed directly onto Bakugou's desk.

 _Kacchan._

Everyone steeled themselves, anticipating the worst. Izuku felt his right hand clench into a fist, preparing to use All-for-One to smash whatever threat into oblivion. _And if it came down to it, to protect Kacchan_ _if his life was in any sort of jeopardy._

"What the fuck…what the _fuck_ was that!"

Everyone let out a collective sigh of relief.

Bakugou was still alive.

He saw Bakugou furiously attempt to stand up amidst the rubble, face full of soot and grime, body filled with small cuts and bruises from the unexpected blast.

And the expression on his face was nothing short of outright _murderous_.

They all peered over to look at the cause of the attack.

There, sprawled down on the ground and laying on his back, was an unconscious young man.

Izuku blinked to make sure that he wasn't looking at an illusion caused by the hit to his head. A quick glance around told him that everyone bore the same flabbergasted reaction.

He looked foreign. Like an American. And he was admittedly handsome except for the ugly slash on the left side of his face, a scar just like Todoroki's.

But the biggest glaring suspicion about him was the red which colored his entire left side. Blood.

No way. The guy didn't even look that much older compared to them.

A villain.

He had to be a villain.

For some reason, everyone just stood in shock, not daring to move.

And then the guy's eyes opened.

His eyes were a brilliant, unnatural gold.

 _Something's not right._

There was something vaguely weird about him, as though he shouldn't exist but he did.

Izuku wanted to throw up from the guy's presence.

 _Who…who are you?_

He stood up, slowly, carefully, dusting off the dirt that clung to him and stretched his arms, as if crash-landing from the sky and straight into a classroom was nothing out of the ordinary. He popped his neck joints and grunted, and paused when he noticed them watching him. Immediately, he straightened up, settling onto a comfortable posture while flexing his shoulder. Golden eyes roamed over the entire room, at all of them, like he was trying to memorize all their faces and features. Everyone was frozen in shock.

Even Bakugou went still.

From the corner of his eye, he saw Todoroki tense up and Yaoyorozu materialize a spear and shield. His own middle finger started tingling like crazy. In situations like this, it was either fight-or-flight, and he was prepared to do the former.

"Who the hell are you, asshole?" Bakugou managed to shout, and for once Izuku was glad that his childhood friend was able to have his anger overtake his fear. "Messing me up like that…you looking for a death wish?"

The strange guy said nothing, but his eyes glanced towards Bakugou's direction.

And then he spoke. It was in a weird language Izuku didn't understand, but he was sure it wasn't English at all. His voice sounded… _cold_ , and deep, which didn't fit his appearance at all. It sent chills down his spine.

The stranger spat blood on the ground, and Bakugou exploded. "What the fuck are you spewing?! Whatever, it doesn't matter. You're going to _die_!"

"Kacchan, stop! We don't know _who_ he is. Let's try not to aggravate him until the teachers arrive-"

"Shut up, Deku!"

Before he could stop him, Bakugou raised his hand, small explosions already forming on his palm-

-and then he stopped.

Izuku blinked in confusion.

Why wasn't he moving?

Wait.

No.

He _was_ moving.

But there was only a slightest hint of movement in his body, as though time was set in a very, very slow motion. It was almost as though he had been paralyzed.

"Is this for real? Like, seriously?" Kaminari muttered disbelievingly.

Izuku wanted to record what he was seeing despite himself.

 _Time manipulation? That's his quirk?_

 _That's insane._

Before anyone could blink, the stranger flicked his wrist and Bakugou instantly collided to the wall like a limp ragdoll. Beside him, Hagakure Tooru screeched as the wall cracked and Bakugou crashed down to the floor, choking and wheezing for air.

Izuku's heart was pounding.

 _He hurt Kacchan._

 _He didn't even touch him! What was that, a kind of telekinesis?_

 _He was_ _ **dangerous**_

It was now or never.

Without thinking about it, Izuku raised his right arm and willed the power of All-for-One inside his finger…

…and stopped.

He couldn't move.

No.

He _could_ move.

But.

But it felt like he was trapped inside a jelly container. He was moving very, _very_ slowly, a centimeter each passing five seconds.

He willed his body to move. _Come on, move!_

To his left, Todoroki already had his ice out but was also not moving normally. Iida was stuck in mid-run. Bakugou was still lying down on the floor, silently seething, mouth in a snarl and eyes full of unrepressed rage.

 _Oh god_. Everyone was in the same predicament. They were all suspended…frozen in time.

As if someone hit the "pause" button in a movie.

It was a nightmare.

The unknown stranger calmly walked around the room, boots loudly stepping on the rubble on the ground. Izuku's eyes slowly followed his movement. When he passed by Izuku, the otherworldly, domineering presence that surrounded him made the student shiver. Izuku shook with a similar fear he hadn't felt ever since Tomura Shigaraki almost touched him and left him as a pile of ashes flying in the wind.

He casually roamed around the room as if he was just strolling in a park, as if freezing time was a daily occurrence for him. Looking at every single one of them.

He stepped foot on the teacher's spot, in front of the whole class.

He turned around, and everyone could see his eyes like molten gold, glinting with amusement.

They all held their breaths.

A horrid, inhumane smile contorted on his face.

When he spoke again, it was in that weird language again which they didn't understand, but from the way his voice was laced with barely contained malice, it was clear that it wasn't anything good.

 _He was dangerous._

 _He was a bad guy._

Izuku wanted to cry out in fear. Where was All Might? Mr. Aizawa? Someone…someone- _anyone_ -a hero should save them!

Suddenly, the stranger coughed. Blood dribbled down the side of his mouth, and he wiped it away in disgust, and just as he glanced towards them again-

-the front door opened, revealing a sullen-looking man.

 _Mr. Aizawa._

And he looked downright _pissed_.

"What's all the noise…" his voice died down as he scanned the whole room. And then he locked eyes with the golden-eyed stranger. He instantly tensed up, but his eyes were now smoldering, looking absolutely, utterly mad.

"I leave you alone for five minutes, and you've already found trouble," he muttered under his breath. "Or it seems like trouble has found you instead. Now who might you be?"

For a few seconds, the frightening guy seemed to be in a stare-down with their homeroom teacher. Blood was still slowly pouring out of his mouth, his nose, his left side. He swayed a little; he opened his mouth and at the same time Mr. Aizawa activated his quirk-

-and the stranger slumped down, unconscious.

It was so sudden no one knew how to react.

 _What-_

Izuku could move his limbs again.

He could _move_ again.

He was so glad he felt fat tears sliding down his cheeks.

Instantaneously, everyone started to freak out.

"That fucking bastard…the fuck…"

"Guys, did that really happen? Was that real?"

"What the hell, dude. That was _crazy_!"

Mr. Aizawa wordlessly crouched down and checked the guy's pulse.

"Iida, help me carry him over to the clinic. Let's have Recovery Girl fix him up."

"With all due respect Aizawa-sensei, I personally don't think that's a wise decision-"

"We can't interrogate him if he's half-dead. Now get moving."

He turned and addressed the whole class. "And all of you, stay put here. The test will be temporarily stopped. Yaoyorozu, keep order inside the classroom."

"Y-Yes, Aizawa-sensei."

And, with a tone that didn't tolerate any nonsense, he said, "Behave, or else."

After he was gone, the entire class resumed talking with each other despite being utterly terrified a few minutes ago. Bakugou was so angry that his desk along with his test paper got destroyed, he was setting off explosions after another while screaming profanities. The other classes decided to see what the noise and ruckus was about, no doubt thinking that Class 1-A was up to trouble again.

Some of the students gaped at the huge hole created in the classroom ceiling; several feet of concrete were destroyed.

The entire school would be buzzing about them. Again.

"That guy…I bet he's from the League of Villains."

"Are those bastards stirring up trouble again?"

"We just can't take a break, huh? The attack at USJ just happened a week ago. I can't believe they have the audacity to attack inside the heroes' home turf! _Again_!"

"Thank God, teach was here to save us."

"Yeah, he's so cool when he's not trying to look worn-out or something."

"Idiot, don't let him hear you say that."

"Hey, I'm just saying."

"Everyone, please pipe down!"

"Sorry, Momo…"

"Bakugou, you should go to the clinic as well! That crazy dude slammed you around like it was nothing!"

" _What the fuck did you just say,_ hair-for-brains? You take that back right now or _you're_ the one who's gonna get slammed around!"

"Woah, chill. Kirishima's just concerned."

"Kirishima's right. You should go to the clinic to check for injuries."

"Shut up, ponytail-bitch! I'm not some weak little shit. It doesn't hurt at all!"

"You're such a bad liar…"

"Our classroom is a mess. There's dust everywhere!"

"Ugh, it even got on my clothes…"

"It'll be such a hassle to clean this up."

"Hey Mina, don't sneeze in my direction!"

"Sorry!"

"Does anyone else find it funny that out of all of us, Bakugou's desk is the only that's destroyed?"

" _I'll get you, you little shit!"_

Izuku just stared at the ground quietly, mind reeling.

He was sweating.

A hand carefully touched his shoulder.

"Deku?" Uraraka. Her voice sounded worried. "Are you…okay?"

He looked up and met her concerned eyes.

He forced a weak smile. "Yeah…yeah, I'm okay. Just shocked, is all."

Inside, he was screaming _no no no._

She squeezed his shoulder. "I…I understand," her voice wavered. "Not being able to move...it was terrifying. I thought he was going to kill us all. There's just no rest for us, is there?"

Izuku winced at her self-depreciating tone. "I guess not. But it's okay. He's gone now."

But despite saying that, a small voice nagged inside his head.

Something told him that it wouldn't be the last they saw of the guy.

* * *

He was dreaming.

Dreaming of days when he was still on the run with Thalia and Annabeth. A time when he was still happy, even if it was just fleeting, momentary.

He also dreamt of Kronos's cold, sarcastic laugh. And darkness. Total darkness.

And then he opened his eyes.

The first thing he thought when he woke up was-

 _I never got to ask Annabeth if she ever loved me._

Blue eyes stared at the bright, fluorescent lights above him.

 _Castellan,_ Kronos seethed. _We are not in our world anymore. The energy in here is unusual._

 _Congrats. You fucked up,_ Luke thought.

He closed his eyes and went back to sleep.

* * *

 **A/N: Because I just can't get enough of writing BNHA crossovers.**

 **I'm sorry guys. I should be updating** _ **Bow to the Sun**_ **and** _ **Tabula Rasa**_ **, but this plot bunny held on to my neck and wringed it until I finally finished writing this. I'm currently finishing Chapter Two of** _ **Tabula Rasa**_ **and maybe about half-way done with Chapter Four of** _ **Bow to the Sun.**_ **I'm still busy with lots of stuff, but I'm hoping I can make time to update my other stories.**

 **Also, I've just realized that I'm fond of writing characters who, coincidentally, all have golden eyes. Lol.**

 **For anyone who's not familiar with Kronos, he's the major antagonist in the first series of the Percy Jackson books. And Luke is his chosen vessel or host, because he can't use his full form yet. It's a bit complicated, so if you're interested, you should read PJO. Literally one of the best fantasy/adventure book series of all time. He's also crazy OP, I'm not kidding, search his feats. Although there's something in this story (not telling) that's gonna restrict his powers. Rest assured, he's not going to be able to murder everyone. (Not yet anyway lmao.)**

 **What are your thoughts? Leave a review!**


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